"perché mai" meaning in Italian

{
  "head_templates": [
    {
      "args": {},
      "expansion": "perché mai",
      "name": "it-adv"
    }
  ],
  "lang": "Italian",
  "lang_code": "it",
  "pos": "adv",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Italian entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "english": "Why on earth would I pay for a service that I don't use?",
          "text": "Perché mai dovrei pagare per un servizio che non utilizzo?",
          "type": "example"
        }
      ],
      "glosses": [
        "why on Earth"
      ],
      "id": "en-perché_mai-it-adv-dnNUHA82",
      "links": [
        [
          "why on Earth",
          "why on Earth"
        ]
      ],
      "raw_glosses": [
        "(idiomatic) why on Earth"
      ],
      "tags": [
        "idiomatic"
      ]
    }
  ],
  "word": "perché mai"
}

{
  "head_templates": [
    {
      "args": {},
      "expansion": "perché mai",
      "name": "it-adv"
    }
  ],
  "lang": "Italian",
  "lang_code": "it",
  "pos": "adv",
  "senses": [
    {
      "categories": [
        "Italian adverbs",
        "Italian entries with incorrect language header",
        "Italian idioms",
        "Italian lemmas",
        "Italian multiword terms",
        "Italian terms with usage examples"
      ],
      "examples": [
        {
          "english": "Why on earth would I pay for a service that I don't use?",
          "text": "Perché mai dovrei pagare per un servizio che non utilizzo?",
          "type": "example"
        }
      ],
      "glosses": [
        "why on Earth"
      ],
      "links": [
        [
          "why on Earth",
          "why on Earth"
        ]
      ],
      "raw_glosses": [
        "(idiomatic) why on Earth"
      ],
      "tags": [
        "idiomatic"
      ]
    }
  ],
  "word": "perché mai"
}